Motor fuel product



Patented Nov. 27, 1934 V MOTOR FUEL PRODUCT Thomas Hunton Rogers and Vanderveer Voorhees,

Ind., assignors, by mesne asignments, to Gasoline Antioxidant Company, Wilmmgton, Del., a corporation of Delaware No Drawing. Application February 2, 1934, Serial No. 709,454

'lClaims.

The present inventionrelates to improvements in hydrocarbon motor fuel products of the charv acter of gasoline, and has to do more particularly with motor fuel products derived'by the crack- 5 ing of higher boiling hydrocarbon oils of such types as display a tendency to form gum or resinification products on storage, even after refining treatment with a dilute sulfuric acid such as sulfuric acid of 75% strength or lower. This tendency may be indicated by an accelerated test designated hereinafter as the oxygen absorption test, which is a measure of the potential gum formation or resinification properties of the motor fuel products.

In methods of cracking high boiling hydrocarbon oils to produce lower boiling hydrocarbon oils, the products which have been secured may in general be grouped in two classes; the first, which at the present time forms the bulk of pressure cracked gasoline, having an anti-knock value somewhat, greater but not substantially greater than straight-run gasoline; a somewhat lower Baum gravity than straight-run gasoline; containing a moderate proportion of unsaturated compounds as determined by combined absorption and polymerization by sulfuric acid in accordance with the method of determination hereafter set forth; and being in general of such a character that the constituents thereof which tend to form gum on storagecand handling are readily removed by treatment with sulfuric acid to produce a product comparable in that respect to straight-run gasoline. Motor fuel products of the second general class, hitherto derived principally from vapor phase processes or very high temperature pressure cracking processes,

have antiknock values substantially higher than straight-run gasoline; have a much lower A. P. I.

gravity; contain large amounts of unsaturated compounds as determined by sulfuric acid absorption and polymerization; and "require excessive treatment with sulfuric-acid with very substantial losses, to remove potential gum-forming constituents.

Although it cannot be said that there is a hard and fast line between'the two types of products, the former type of product, with 425 F. end point, will in general have an anti-knock value not exceeding an equivalent of 1.2 cubic 50 centimeters of tetra-ethyl lead per gallon of straight-run Mid-Continent gasoline; an olefin content as determined by sulfuric acid absorption and polymerization of not over 40%: an A.

P. I. gravity of 56 to 59: and anoxygen absorp 55 tion induction period greater than 125 minutes,

as determined by the test hereinafter set forth. The second type of product, which may be designated as the vapor phase type, will in general have an anti-knock value equivalent to at least 1.2 cc. tetra-ethyl lead per gallon straight-run Mid-Continent gasoline, an A. P. I. gravity of about 49 to anunsaturated content as determined by sulfuric acid absorption and polymerization exceeding 40%, and usually above 45%; and an oxygen absorption induction period of less thanl25 minutes.

The latter type of product in general tends to form gum, even on storage in the dark, and under like conditions, tends to lose its anti-lmockproperties. The same tendencies may exist, to a greater 7 or less extent, in products of the first mentioned type and, the present invention may be employed in connection therewith, although particularly I intended. for use in connection with productsof the so-called vapor-phase cracked type.

Thus, products of certain processes commonly designated as liquid phase or liquid-vapor phase cracked products, although having a lower unsaturated content than vapor phase cracked products, as shown by combined absorption and polymerization by sulfuric acid, have gum-forming properties similar tothose of vapor phase cracked products. The present invention may be applied in connection with such products, m well as with such highly cracked products as are derived by drastic or high temperature cracking or destructive distillation of bituminous materials, such as coal, peat, lignite, and the like. For example, crude benzol or blends of benzol and gasoline.

In determining the oxygen absorption induction period. by which an indication of the potential gum-forming properties of the gasoline on storage and handling may be secured, the following procedure may be employed; 100 cubic centimeters of the motor fuel or gasoline to be tested are placed in a one liter flask, the total volumetric capacity of which is 1150 to 1200 cubic centimeters. The gasoline is maintained at about 212 F. by heating in a steam bath while an oxygen atmosphere is maintained in the flask under a substantially constant pressure of about 2 2 atmospheres. The flask is vigorously agitated and the volume of oxygen absorbed-is measured at frequent intervalsv The oxygen absorption is characterized by an initial period in which relatively small amounts are absorbed and subsequent to this period there is a rapid increase in the rate of absorption. This initial period of slow absorption is designated the induction period, and its end is regarded as the point at which oxygen absorption under the conditions stated reaches a rate of 1 cubic centimeter per minute. If the oxygen absorption is plotted against the time in minutes with equal distances on the coordinates for time in minutes and absorption in cubic centimeters, it will be evident that theend of the induction period will be indicated upon the curve by the point where the tangent to the curve has a slope of 45. The length of the induction period, as determined by this test, provides a fairly accurate indication of the potential gum-forming behavior of the motor 'fuel product on storage and handling.

'The motor fuel products with which the present invention is primarily concerned, are produced from cracked distillate products of the vapor-phase cracked type which, after treatment with dilute sulfuric. acid of 50 to 70% strength, have an oxygen absorption induction period of less than 125 minutes. The following procedure has been employed in producing such a product.

A hydrocarbon oil, preferably a distillate product heavier than gasoline, is forced through a continuous coil in a heating zone and brought therein to an outlet temperature of 825 to 975 F. while maintaining thereupon a pressure exceeding 200 lbs. under conditions to produce from 15 to of hydrocarbons in the gasoline boiling point range in theproducts leaving the coil. The

material leaving the coil is preferably reduced in pressure and fractionally condensed to separate the hydrocarbons in the gasoline range of boiling points as a distillate, The vaporization is controlled, or the distillate product may be rerun, to produce a material conforming to the desired specifications, for example, to 425 F. end point. Such a material has a gravity of 48 to 56 Baum' as compared with 58 to 60 Baum for a straight-run gasoline of similar boiling range from Mid-Continent crude. The product, without treating, is found to have an oxygen absorption induction period of about 35 to minutes. It is suitably treated with dilute sulfuric acid, say 60% acid, to the extent of 6 lbs. of such acid per barrel of distillate. The loss on treating is about. the color of the product is not substantially altered, but is substantiallystabilized and the oxygen absorption induction period is increased to to 90 minutes. In determining the unsaturates in such a product it shows a combined absorption and polymerization loss of 50% to 70% when the test is made with 90% sulfuric acid. This loss is determined by subjecting a given volume of the material to treatment at room temperature with two volumes of 90% sulfuric acid, separating the remaining oil from the acid layer and redistilling the unabsorbed oil to produce a distillate having the same end point as the original material treated. The loss in volume relative to the original material is that which is designated as the combined abso tion and polymerization loss.

eral, of less than 0.1% and preferably less than 0.05%, and substantially stabilize motor fuel products againstthe gum formation and resinification and also against loss in antiknock. This stabilization is indicated by an increase in the oxygen absorption induction period of the products to which they are added. As examples 'of such materials we may employ the nitroso naphthols such as alpha-nitroso-alpha-naphthol, nitroso-naphthylamines such as nitroso naphthylamine (5,2) and para-nitroso naphthylamine. The alphanitroso-alpha-naphthols arel-i, 1-5, 1-8, nitroso naphthols. Corresponding compounds derived from other condensed ring hydrocarbons such as anthracene and phenanthrene having reducing properties may be employed when permitted by considerations of cost and absence of color.

The specific activity of the materials varies to a considerable extent, all of them, however, being effective in inhibiting the gum forming properties of the motor fuel product and preventing its deterioration, for example, by decrease of its antiknock value, and these properties are indicated by an increase in the induction period of the product. Thus with a product such as that above described and which, after dilute acid treatment, has an induction period of 55 minutes and a lead equivalent of 1.7 cubic centimeters tetra-ethyl lead per gallon of straight-run Mid-Continent gasoline, the addition of 0.1% to 0.05% of a nitroso naphthol or nitroso amine increases the induction period to at least 130 or 140 minutes.

- The results secured by the application of the oxygen absorption test, as hereinbefore described, definitely indicate the behavior of the motor fuel product on storage, both in its tendency to form gum and to lose antiknock value. Thus, fuels treated in accordance with the present invention on storage over periods such as those customary in commercial operations, say 6 or 8 months, have their normal loss of antiknock value and increase of gums and gum forming constituents materially reduced or substantially entirely eliminated.

This application is a continuation in part of our copending application 476,717 filed August 20, 1930.

We claim:

1. A motor fuel comprising cracked hydrocarbon distillates' normally tending to deteriorate and develop gums on storage and containing a small proportion of a nitroso derivative of a compound selected from the group consisting of a naphthylamine and a naphthol, in quantity sufficient to inhibit such gum formation.

2. The method of preserving cracked hydrocarbon distillates which normally tend to deteriorate and develop gums on storage by incorporating therein a small proportion of a nitroso naphthylamine in quantity suflicient to exert a substantial inhibiting effect upon such deterioration and gum formation.

3. A motor fuel comprising cracked gasoline normally tending to deteriorate and develop gums on storage and containing a small proportion of an alpha-nitroso-alpha-naphthol in quantity sufficient to exert a substantial inhibiting effect upon deterioration and gum formation therein.

4. A motor fuel comprising an admixture of cracked gasoline and benzol which normally tends to deteriorate and develop gum on storage and containing a small proportion of a nitroso derivative of a compound selected from the group consisting of a naphthylamine and a naphthol, in quantity sufiicient to inhibit such gum formation.

5. A motor fuel comprising a cracked gasoline normally tending to deteriorate and develop gums on storage and containing a small proportion of a nitroso naphthylamine in quantity suilicient, to exert a substantial inhibiting effect upon such gum formation. v

6. The method of preserving cracked hydrocarbon distillates which deteriorate and develop gums on storage by incorporating therein a small proportion of a nitroso naphthol in quantity suf- 

